Blast nozzles for melting furnaces



Feb. 21, 1956 B. AURIN ET AL 2,735,409

BLAST NOZZLES FOR MELTING FURNACES Filed Dec. lO, 1952 2 Sheets-Sheet l Feb- 21, 1956 B. AURIN ET A1.

BLAST NOZZLES FOR MELTING FURNACES 2 Sheets-Sheet 2 Filed DeC. l0. 1952 United States Patent O BLAST NOZZLES FR MELTING FURNACES Bruno Aurin, Hemer (Westphalia), and Willi Dehne, Dortmund-Horde, Germany, assignors to Herr Emst Thomas, Hemer (Westphalia), Germany Application December 10, 1952, Serial No. 325,184 Claims priority, application Germany December 11, 1951 7 Claims. (Cl. 122-6.6)

In melting furnaces, particularly blast furnaces, use is made of nozzles or tuyeres for ejecting hot air into the furnace space, which are connected to the air supply pipe, pass through the furnace wall, and project by only part of their length into the furnace space. In blast furnaces the position of the nozzles is selected slightly above the surface of the slag. Nozzles of this type are in particular exposed to the temperature prevailing in the furnace and stressed by the material falling down during the re-lling of the furnace.

The invention relates to` blast nozzles or tuyeres of the type which are constructed as liquid-cooled hollow bodies and have an attached hollow nozzle head, the annular chamber of which is connected direct to the cooling medium supply pipe.

According to the invention, a very substantial improvement is achieved in respect of the cooling of blast nozzles, and hence an increase in dependability in operation, by the fact that at least the outer surface of the hollow body is formed of a spirally wound tube included in the circulation of the cooling medium, said tube being taken to a position near the nozzle end while using a short nozzle head provided with a small passage cross-section. The winding of the nozzle surface from tubes presents no diiculty. These tubes of small diameter for the nozzle surface and the simultaneous reduction of the size of the passage cross-section in the nozzle head permit to a degree a controlled circulation of the cooling medium, so that vapour cannot be formed at any point. Even when using tubes with slight wall thickness, a nozzle construction is obtained which is particularly strong and which is also suitable for carrying the cooling medium at high pressure.

The spirally wound tubes of the nozzle surface can be connected to the annular chamber of the nozzle head, so that the cooling medium passing out of the nozzle head then flows through the tubes situated in the rear thereof. A more suitable construction consists in providing separate inlet and outlet pipes for the liquid for the nozzle head and the tubes forming the surface of the nozzle hollow body. In a form of construction in which the inner surface of the nozzle hollow body also consists of a spirally wound tube, the inlet and outlet pipes for the nozzle head can be disposed with complete insulation between the two surfaces composed of tubes.

The nozzle according to the invention is particularly suitable as a blast nozzle for the supply of hot air in blast furnaces. It is however also possible to use this nozzle in other melting furnaces. It is also possible to pass other gaseous or liquid media through the nozzle intead of hot air. It is even possible to use this nozzle as a passage for slag discharge.

An embodiment of the invention is illustrated in the drawings, in which:

Figure l is a longitudinal section of a blast nozzle,

Figure 2 is a cross-section taken on the line 2--2 in Figure l, and

Figure 3 is a side view partly in section of the nozzle of Fig. 1.

The nozzle illustrated in Figure 1 shows a nozzle in which the outer surface is formed of a spirally wound tube 3 and the inner surface is formed of a tube 4a, which has an elongated cross-section and is wound spirally. The spirals of each of the tubes 3 and 4a of the two surfaces have a rectangular cross-section, and abut one another by the shorter facing sides. These tubes have legs 13. Between the legs of the adjoining tube spirals supporting bodies 14 are disposed, which in the exemplified embodiment illustrated can consist of a likewise spirally wound band of steel, copper, or the like. The tube cross-sections are not subjected to compressive stresses, since the tube legs are supported against one another. The nozzle head 5 is provided with an annular space 7, which is divided by a transverse wall 15 (see Figure 2) to form a substantially U-shaped circulating passage, at the ends of which the inlet and outlet pipes for the cooling medium are connected. The cross-section of the divided annular passage 7 in the nozzle head 5 is small, namely not much larger than the cross-section of the tubes 3 and 4a, in order to ensure good circulation of the cooling medium in the highly stressed nozzle head. The nozzle head is fastened to the other parts of the nozzle, particularly the rear part 16, by retaining screws or anchors 8b, one of which can be constructed as a cooling water inlet pipe 8. In the same way, the cooling water return pipe 8a can also be constructed as an anchor. The nozzle head 5 may however also be joined by welding to the connecting surfaces of the nozzle body. ln this exemplified embodiment the liquid is passed to the annular chamber 7 of the nozzle head 5 through the pipe 8, and is returned to the outside direct through the pipe 8a. A separate cooling medium inlet pipe 17 (see Figure 3) is provided for the nozzle surfaces formed by the tubes 3 and 4a, this pipe being connected to the rear end of the outer surface. The outer tubular surface and the inner tubular surface are connected together near the nozzle head by the connecting pipe 18, in such manner as to conduct the liquid, so that the liquid supplied through the pipe 17 is passed off through the pipe 19 after passing through the inner tubular surface. The nozzle head 5 is one piece in the present instance. In addition, it is pointed out that the anchors or pipes 8, 8a are disposed with particular protection between the tubular surfaces 3 and 4a.

A copper alloy which is particularly resistant to heat is preferably used as the material for the nozzle head and the tubes of the nozzle surfaces. There is however nothing to prevent the use of other suitable material. The tubes used for the production of the surfaces may be welded or seamless drawn tubes. The tubes themselves are given the smallest possible cross-section in relation to the size of the nozzle, so that the cooling medium flows as uniformly as possible over all parts of the nozzle, while on the other hand, despite the use of thin wall thicknesses for the individual parts, the nozzle body has great strength.

We claim:

1. A blast nozzle comprising a hollow nozzle head in the form of a hollow ring-shaped chamber, a rear closure part in the form of a ring, a conical internal tube forming a uid passage extending from and connected to the rear part and to the nozzle head, a spirally wound tube forming a conical outer cover between the nozzle head and the rear part and spaced from the conical internal tube, the spiral tube being in contact as to adjacent spirals and forming a smooth conical outer surface, means to secure the conical internal tube and the spirally wound tube between the nozzle head and the rear closure part including means in the space between the conical internal Patented Feb. 21, 1956.

tube and, the spirally wound tube to admit uid to circulate into thev nozzle. head, and, an inlet, and. an outlet through the rear closure part for a cooling fluid connected to the spirally wound tube and the conical internal tube.

2. A blast nozzle according to claim 1, in which the conical internal tube is formed as a spiral tube similar to the first-mentioned spirally wound tube, and in which interconnecting means are provided for the two spirally wound tubes.

3. A blast nozzle according to claim l, in which the conical internal tube is formed as a spiral tube similar to the first-mentioned spirallywound tube, and in which interconnecting means are provided for the two spirally wound tubes, said second-mentioned means including a pair of tubesl separated by a wall member in the nozzle 4 head and extending between the two spirally wound tubes to admit and discharge the uid to and from the nozzle head.

4. A blast nozzle according to claim 1, in which the conical internal tube is formed as a spiral tube similar to the first-mentioned spirally wound tube, and in which interconnecting means are provided for the two spirally wound tubes, said spirally wound tubes each having a rectangular cross section with the shorter sides in contact with each other as to two adjacent tube coils.

5. A blast nozzle according to claim 1, in which the 4 Y conical internal tube is formed as a spiral Vtube similar to the. rfrstrmentioned snrally wound. tube.. and in. which interconnecting means are provided for the two spirally wound tubes, and in which each of the spirally Wound tubes is provided with a longitudinally directed rib.

6. A blast nozzle accordingy to claim 1, in which the conical internal tube is formed as a spiral tube similar to the rst-mentioned spirally wound tube, and in which interconnecting means are provided for the two spirally wound tubes, and in which each of the spirally wound tubes is provided with a longitudinally directed rib and supporting means are also provided cooperating with the ribs of each set of spira/lly wound tubes.

7. A blast nozzle according to claim l, in which the spirally wound tube has a rectangular cross section to provide the conical outer cover.

References Cited in the le of this patent UNITED STATES PATENTS 114,739 Wood, Ir. May 9., 1871 166,617 Lloyd Aug. 10, 1875 248,462 Hartman Oct. 18, 1881 265,156 Sheets Sept. 26', 1882 2,074,507 Henry Mar. 23, 1937 2,454,892 Sprow Nov. 30, 1948 2,540,231 Avery Feb. 6, 195.1 

1. A BLAST NOZZLE COMPRISING A HOLLOW NOZZLE HEAD IN THE FORM OF A HOLLOW RING-SHAPED CHAMBER, A REAR CLOSURE PART IN THE FORM OF A RING, A CONICAL INTERNAL TUBE FORMING A FLUID PASSAGE EXTENDING FROM AND CONNECTED TO THE REAR PART AND TO THE NOZZLE HEAD, A SPIRALLY WOUND TUBE FORMING A CONICAL OUTER COVER BETWEEN THE NOZZLE HEAD AND THE REAR PART AND SPACED FROM THE CONICAL INTERNAL TUBE, THE SPIRAL TUBE BEING IN CONTACT AS TO ADJACENT SPIRALS AND FORMING A SMOOTH CONICAL OUTER SURFACE, MEANS TO SECURE THE CONICAL INTERNAL TUBE AND THE SPIRALLY WOUND TUBE BETWEEN THE NOZZLE HEAD AND THE REAR CLOSURE PART INCLUDING MEANS IN THE SPACE BETWEEN THE CONICAL INTERNAL TUBE AND THE SPIRALLY WOUND TUBE TO ADMIT FLUID TO CIRCULATE INTO THE NOZZLE HEAD, AND AN INLET AND AN OUTLET THROUGH THE REAR CLOSURE PART FOR A COOLING FLUID CONNECTED TO THE SPIRALLY WOUND TUBE AND THE CONICAL INTERNAL TUBE. 